This invention relates to an automotive door latching system, and particularly to a latching system wherein a latch for one door (or closure) has to be in the unlocked (release) position before the latch for a second door (or closure) can be moved from the locked position to the unlocked position. The system ensures that the two doors can only be opened in a particular sequence; i.e. the first door has to be opened before the second door.
U.S. Pat. No. 5,688,004, issued to S. Karge, discloses a door latching system wherein an upper hatch door at the rear of a vehicle has to be opened before a companion lower hatch door can be opened. Each hatch door latch is operated by an electric motorized drive means. An electric switch is associated with the latch for the upper hatch door so that the motorized drive for the latch on the lower door can only be energized when the upper hatch door is in the open position.
The present invention is concerned with a sequentially-operable door (or closure) latch system having a relatively simple operational mode and construction. The latch for the second door (or closure) is controlled by an electrically-operated latch release means that is in series connection with an electrical switch controlled by the latch for the first door, whereby the second door can be opened only when the first door is in the open position. A second master control switch is in series connection with the electrically-operated latch release means, so that the latch release means is disconnected from the electrical power source when the first door is open and the second door is closed. This feature prevents undesired drain on the battery power source.